Dysoxygenosis

Too much oxidation and too little oxygen – those are the molecular clues to the case of the missing toads. Frog corpses were found decomposed or eaten, but the cause of death remained elusive. A partial answer to the mystery was provided by Australian, American, and Canadian researchers last year. The culprit, they reported, was not an alien, but a lowly fungus belonging to the genus Chytridiomycota.17 Significantly, the prior rap sheet of this fungus shows it to infect plants and insects, not frogs. How does the fungus, which affects the frogs’ skin, kill them? The investigators believe the fungus suffocates frogs by clogging their skin pores through which they breathe. It seems likely that the fungus not only mechanically blocked oxygen transport but also caused severe oxidative injury in frogs, as fungi do in humans.

In California, pesticides were reported to be the villains. How do pesticides kill? By poisoning respiratory enzymes of insects. It so turns out that some of those enzymes, such as cholinesterase, are identical to the human cholinesterases. What robs insects of their oxygen supply also suffocates human microecologic cellular systems.

In Chesapeake Bay, during summer months the water oxygen content drops and acidity rises steeply due to heavily contaminated effluent from hog farms draining into coastal marshes. That causes the oxygen-deprived Eastern oysters to lose their immune resistance to the dermo parasite. The aquatic life which succumbed to the Valdez spill also died the same way: too much oxidative stress, too little oxygen.